Of all the MTA employees who are not working on the tracks, bus drivers have it the worst. They are exposed and vulnerable to violent and unruly passengers. Over the weekend, another threat — Halloween pranksters — emerged. Heather Haddon reports on the death of a man who threw a heavy object and shattered a bus window. (For what it’s worth, the Daily News simply called the incident a jaywalking death.) Another bus faced an attack by a BB gun, and city buses are often egged on Halloween. Although the MTA workers tried to help each other out, bus drivers remain in a precarious position when under attack.